Furnace draft regulator



May 13, 1952 E. A. LUCAS FURNACE DRAFT REGULATOR Filed Oct. 27, 1948 wizzai MFAWZS Patented May 13, 1952 FURNACE DRAFT REGULATOR Elmer A.Lucas, Edgewood, It. I.; W. Ward Harvey, Newport, R. I., executor ofsaid Elmer A. Lucas, deceased, assignor to Luella E. Lucas,

Newport, It. I.

Application October 27, 1948, Serial No. 56,691

' 1 Claim. (01. 236-45) This invention relates to a damper forcontrolling the draft in a furnace flue, particularly to a draftregulator which is responsive to sudden gusts or variations of pressurein the flue. A common way of controlling a draft through a furnace is toprovide an opening in the flue near the furnace with a check damper inthe opening which opens with any variation of pressure in the flue toby-pass the furnace, that is reduce the pressure variation transmittedto the furnace. However such a damper is not positive in action, thatis, it merely reduces the increase in draft rather than eliminating thatincrease altogether.

- Furthermore such a check damper does not react quickly to suddendrafts so as to prevent their taking some effect in the furnace.

Objects of the present invention are to provide a draft regulatorresponsive to variations in flue pressure, which is quick and positivein action, and which is simple and efficient in operation.

In one aspect the invention comprises a damper located in the flue whichmoves from between a position in which it blocks the draft through theflue to a position in which it does not impede the draft, a deflatablechamber which is interconnected with the flue and which expands ordeflates in response to variations in the draft in the flue, the chamberbeink linked to the damper by suitable means for moving the damper fromits operative to inoperative position as the chamber responds tovariation in the draft. Preferably the damper is urged towards operativeposition by any commonly used yielding means while the yielding meansare counter-balanced by the movable portion of the chamber so that thedamper does not leave inoperative position until the chamber responds toan increase in the draft. The chamber may be connected with the flueeither directly or through a duct.

In a specific aspect the chamber includes a transverse movable bafliewhich divides chamber into two spaces one of which is interconnectedwith the flue. A change in the draft in the flue will be felt in saidspace and the baffle will move in response to that change.

For the purpose of illustration a typical em-.

bodiment of the invention is illustrated in the accompanying drawings inwhich Fig. 1 is a side elevation of the draft regulator shown inconnection with a furnace, a flue, and a chimney;

Fig. 2 is an enlarged side elevation of the draft regulator like thatshown in Fig. 1; and

Fig. 3 is a side elevation at right angle to the elevation shown in Fig.2.

As shown in Fig. 1 the draft regulating device D is located adjacent aflue B which runs between a furnace A and a chimney C. The draftregulator comprises a damper l in the flue B, a chamber housing 2, aduct 3 interconnecting the chamber and the flue, a coiled spring Gdisposed between a yoke l3 and the axle 9 of the damper which urges thedamper toward open position, a movable baffle or transverse wall 6 inthe chamber suspended by the line 1 from an arm 8 connected to the axle9 of the damper I so as to counter-balance the spring 4.

The chamber within the housing 2 is divided into two spaces H and I2 bythe baffie 6, the upper space ll being connected to and followingchanges of air pressure in the flue B. The baiile 6 is supported andpositioned by a shaft I! which is suspended on the line 1 and extendsthrough the chamber lll2 entering at narrow bore inlets l8 which impedethe flow of air therethrough. The baflle 6 normally rests in the lowerportion of the chamber Hl2 with its weight counterbalanced by the spring4 so that it may be moved upwardly by a small force. A yoke I3 supportsthe bearings I4 of the axle 9 and its supporting post M with the flue 3and the rod it serve to hold the chamber housing 2 in position.

The draft regulator operates as follows. With a normal flow of air andgases through the furnace A, the flue B and the chimney C, the airpressure in the flue B, the duct 3, the upper chamber space I! and thelower space IE will be the same, and the baffle 6 will remain in restposition thus holding the damper l in open position as shown in Figs. 1and 2. However, if there is a sudden change in the draft caused by awindy gust above the chimney or other cause the air pressure in the flue8 will decrease. This decrease in pressure will take effect through theduct 3 on the upper air space I l causing the baffle 6 to rise. As thebaflle rises weight on the arm 8 is reduced and the spring A will beallowed to urge the damper I toward a closed position thus preventingthe increased draft from taking effect in the furnace.

It has been found that this type of draft regulator assures a quickerand more effective check on sudden changes in furnace flue drafts, andrequires little or no attention or adjustment. Also use of this draftregulator obviates the need for providing any opening into the furnaceroom through which soot or obnoxious gases may escape from the flue.

'It should be understood that the present disclosure is for the purposeof illustration only and that this invention includes all modifications3 and equivalents which fall Within the scope of the appended claim.

I claim:

A furnace draft regulating system comprising a furnace, a chimney, aflue interconnecting the furnace and the chimney, a collapsible chamber,a draft regulator for a furnace flue comprising a collapsible chamber, aduct providing unimpeded communication between the chamber and the flue,said chamber having a movable wall responsive to variations in the draftthrough the flue, in the flue between the duct and the furnace a dampermovable between an operative and an inoperative position, and meanslinking-the wall to the damper for moving the latter to an operativeposition as the wall responds to an increase in the draft, said ductbeing connected to the flue intermediate the damper and the chimney,whereby sudden changes in atmospheric pressure transmitted through thechimney are prevented from increasing the draft through the furnace.

ELMER A. LUCAS.

REFERENCES CITED The following references are of record in the.

file of this patent:

UNITED STATES PATENTS 'Niimber Name Date 1,313,447 IWright Aug. 19, 19191,833,064 'Baumann Nov. 24, 1931 2,164,607 Cole July 4, 1939 2,200,669Suman et a1 May 14, 1940 2,246,629 Jansen June 24, 1941 2,441,803 Duiset a1 May 18, 1948

